System and method for proportional mixing and continuous delivery of fluids

ABSTRACT

A system and method for mixing and delivering fluids such as contrast media and saline is disclosed including at least two fluid sources, a pump, a joining fluid path for connecting the at least two fluid sources to an inlet to of the pump, and a valve device in the fluid path upstream of the pump. The valve device includes an actuator adapted to restrict flow in at least one of the respective fluid lines connecting the at least two fluid sources to the pump inlet. A patient interface device may be associated with an outlet of the pump. The valve device actuator is generally adapted to restrict the flow in at least one of the respective fluid lines such that a positional change in valve device actuator position provides a change in fluid mixture ratio of the fluids from the at least two fluid sources to the pump inlet.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a division of application Ser. No. 11/928,021, filedon Oct. 30, 2007, the contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The embodiments of the invention disclosed herein relate generally tothe field of diagnostic and therapeutic medical procedures involving theintravenous infusion of fluids such as contrast-enhanced radiographicimaging as an example and, more particularly, to a system capable ofcontrolled proportional mixing and delivery of fluid mixtures to apatient. In one specific application, contrast media may beproportionally mixed with another fluid such as saline for continuousdelivery to a patient undergoing a medical radiographic imagingprocedure.

2. Description of Related Art

In many medical diagnostic and therapeutic procedures, a medicalpractitioner such as a physician injects a patient with a fluid. Inrecent years, a number of injector-actuated syringes and poweredinjectors for pressurized injection of fluids, such as contrast media(often referred to simply as “contrast”), have been developed for use inprocedures such as angiography, computed tomography (“CT”), ultrasound,and NMR/MRI. In general, these powered injectors are designed to delivera preset amount of contrast at a preset flow rate.

Angiography is an example of a radiographic imaging procedure wherein apowered injector may be used. Angiography is used in the detection andtreatment of abnormalities or restrictions in blood vessels. In anangiographic procedure, a radiographic image of a vascular structure isobtained through the use of a radiographic contrast medium which isinjected through a catheter. The vascular structures in fluid connectionwith the vein or artery in which the contrast is injected are filledwith contrast. X-rays passing through the region of interest areabsorbed by the contrast, causing a radiographic outline or image ofblood vessels containing the contrast. The resulting images can bedisplayed on, for example, a video monitor and recorded.

In a typical contrast-enhanced radiographic imaging procedure such asangiography, the medical practitioner places a cardiac catheter into avein or artery. The catheter is connected to either a manual or to anautomatic contrast injection mechanism. A typical manual contrastinjection mechanism includes a syringe in fluid connection with acatheter connection. The fluid path also includes, for example, a sourceof contrast, a source of flushing fluid, typically saline, and apressure transducer to measure patient blood pressure. In a typicalsystem, the source of contrast is connected to the fluid path via avalve, for example, a three-way stopcock. The source of saline and thepressure transducer may also be connected to the fluid path viaadditional valves, again such as stopcocks. The operator of the manualsystem controls the syringe and each of the valves to draw saline orcontrast into the syringe and to inject the contrast or saline into thepatient through the catheter connection.

Automatic contrast injection mechanisms typically include a syringeconnected to a powered injector having, for example, a powered linearactuator. Typically, an operator enters settings into an electroniccontrol system of the powered injector for a fixed volume of contrastand a fixed rate of injection. In many systems, there is no interactivecontrol between the operator and the powered injector except to start orstop the injection. A change in flow rate in such systems occurs bystopping the machine and resetting the injection parameters. Automationof contrast-enhanced imaging procedures using powered injectors isdiscussed, for example, in U.S. Pat. Nos. 5,460,609; 5,573,515; and5,800,397.

It is often desirable to deliver a mixture of contrast and a diluentsuch as saline to the patient undergoing the radiographic imagingprocedure. Depending on a patient's particular physical characteristics,age, and the tissue to be imaged, the desirable concentration ofcontrast media varies. Medical practitioners can purchase pre-mixedsolutions of contrast media in various discrete concentrations and thisis a common practice in the medical field. Presently, contrast media isprovided in sterilized glass bottles ranging in size from 20 ml to 200ml. Plastic packages are also available. Presently used contrast mediacontainers are single use which means that once a container is openedits contents must all be used for one patient and any residual unusedcontrast and the bottle must be discarded. As a result, a medicalfacility must purchase and stock many concentrations in multiplecontainer sizes to provide the right amount of the right contrastconcentration for a specific procedure while minimizing wastage ofcontrast remaining in any opened containers. This multitude of sizes andconcentrations increases costs throughout the contrast supply chain.Contrast manufacturers are required to make many batches with variousconcentrations and package each in differently sized containers. Themanufactures must have inventories of each concentration/container sizeon hand to quickly meet their customers' requests. Each concentrationlevel and container size also entails an added regulatory burden.

In the end-use medical facility environment, there are additional costsdue to the efforts required to purchase and stock variousconcentration/container sizes. Bulk storage space is required forstocking and cabinets are required in each procedure room. Moreover,labor and time are required to make sure the correct numbers of eachcontainer are kept in each procedure room. Finally, the present systemresults in waste and/or less than optimal studies if this complicatedlogistics chain fails at any point.

Presently, most medical facilities utilize a standard protocol for agiven set of indications. For instance, for a CT scan of the liver, theprotocol may call for 130 ml of contrast injected at 3 ml/s. Thisprotocol is used for a wide variety of patient weights and physicalconditions. One goal of this standardization is to minimize errors.Another goal is to decrease the likelihood of having to repeat theprocedure, with the accompanying additional radiation and contrast doseto the patient. However, there are costs associated with this method.Many patients may get more contrast than they need for an image to bediagnostic. Overdosing wastes contrast but there is no way with thepresent contrast supply and delivery system to remedy this withoutstocking many more sizes of containers and being more judicious in thefilling of injection syringes. Other patients may have studies that areless than optimal as they do not receive enough contrast and there is amuch greater chance of having to repeat the procedure.

In angiography, there are no set protocols to the same extent as in CTbecause patient size determines vessel size which in turn determines thevolume and flow rate required. This means that a fixed amount ofcontrast cannot be prepared ahead of time with any confidence that morewill not be needed during the procedure or that a significant amountwill not remain and be wasted at the end of the procedure. To avoiddelays during an angiography procedure, the medical practitionertypically loads more contrast than the average amount to be used withthe realization that some contrast is likely to be wasted.

A further result of the foregoing system is the accumulation of asignificant amount of hazardous medical waste at the conclusion of theprocedure. To save contrast, several small glass bottles may be openedper patient, one or more plastic syringes may be used, and varioustubing arrangements may be used. Each of these items has an associatedcost to purchase the item and an associated cost to properly dispose ofthe item.

Solutions have been proposed to overcome the foregoing problemsassociated with the use of a multiplicity of concentrations andcontainer sizes and, further, to allow for more individualized contrastmixtures to be produced to meet individual patient requirements. Forexample, U.S. Pat. Nos. 5,592,940 and 5,450,847 to Kampfe et al.disclose a mixing system that allows for mixing contrast medium andsaline “on site” at a medical facility. More particularly, the Kampfe etal. patents disclose an exemplary mixing system that involveswithdrawing or removing predetermined amounts of contrast medium and adiluent (e.g., saline) from respective vessels and mixing these fluidsin a mixing chamber and then delivering the mixed fluid to a suitablereceiving container, such as a vial, bag, or syringe which is used todeliver the mixed fluid to a patient. Other contrast-diluent mixingsystems are known from U.S. Pat. Nos. 6,901,283 to Evans, III et al. and5,840,026 to Uber, III. et al., the disclosures of which areincorporated herein by reference. U.S. Pat. No. 7,060,049 to Trombley,III et al. discloses a system for injecting a multi-componentenhancement medium into a patient that incorporates an agitatingmechanism to maintain the medium in a mixed state for injection and thispatent is also incorporated herein by reference. Within therepresentative “mixing” systems disclosed in the foregoing patents,simple mechanical mixing devices are used to mix the respective fluids.For example, in the systems disclosed by Evans, III et al. and Uber, IIIet al., the fluids to be mixed are joined together as they flow througha static mixer that contains helical vanes. In the Kampfe et al.patents, a bulk mechanical mixer is used to mix two sequential flows. Ineach of these cases, fluid mixture proportions are determined bycontrolled metering valves or other devices (e.g., peristaltic pumps) inthe flow path.

Other devices are known for use in fluid delivery systems having medicalapplications to mix and dispense a mixed fluid, for example, in presetand “fixed” concentration ratios. For example, a selector valve such asthat disclosed in U.S. Pat. No. 3,957,082 to Fuson et al. is known toallow an operator to “dial-in” a selected fluid choice or mixture offluids in a preset or predefined ratio. The Fuson et al. patent allowsfor the choice of a first fluid such as a drug, a second fluid such assaline, or preset “fixed” mixture ratio of the two fluids (e.g., a50%-50% mixture) for delivery to a patient. U.S. Pat. No. 6,918,893 toHoude et al. discloses a selector valve having specific application inthe delivery of contrast and saline in contrast-enhanced radiographicimaging procedures but this selector valve does not have the ability todial in a desired mixture ratio of two fluids. The disclosure of U.S.Pat. No. 3,957,082 is incorporated herein for the selector valveteaching of this disclosure.

Double or dual pinch valves are also known for use in fluid handlingsystems to accomplish one or more of: alternating the flow of twofluids, blocking flow of the two fluids, or permitting simultaneous flowof the two fluids in a fluid path as disclosed in U.S. Pat. Nos.2,985,192 (Taylor et al.); 3,411,534 (Rose); 3,918,490 (Goda); 4,071,039(Goof); 4,259,985 (Bergmann); and 4,484,599 (Hanover et al.). U.S. Pat.No. 6,871,660 to Hampsch discloses a solenoid operated double or dualpinch valve to provide alternating flow capability in a devices used inmedical and pharmaceutical laboratory research. The various double ordual pinch valves disclosed in the foregoing patents, as indicated, havethe ability to control the flow of the respective fluids through twochannels by pinching none, one, or both of the channels through thepinch valve. Accordingly, these pinch valves allow for one channel to becompletely open and the other to be completely closed so as to allowonly one fluid to pass through the pinch valve, allow for both channelsto completely open, or completely block both channels. As a result,these pinch valves provide no ability to mix or control the proportionalmixing of two or more fluids in any desired proportion as provided inthe embodiments disclosed herein in this disclosure. Such ability to mixor, more clearly, control the proportional mixing of two fluids has beenattempted by varying the respective speeds at which two respective pumpdevices deliver fluids to a mixing fluid path, such as disclosed in U.S.Pat. No. 3,935,971 to Papoff et al., but such a system is in practicedifficult to control as it involves regulating precisely motor speed ofthe motors driving the respective pump devices. As a result, suchcontrolled, dual pump systems do not present a very accurateproportioned mixture to the output or delivery conduit. The foregoingshortcomings are overcome by the various embodiments described herein.

SUMMARY OF THE INVENTION

In one embodiment, a system for mixing and delivering fluids such ascontrast media and a diluent such as saline is disclosed comprising atleast two fluid sources, a pump, a joining fluid path connecting the atleast two fluid sources to an inlet to the pump, and a valve device inthe fluid path upstream of the pump. The valve device comprises anactuator adapted to restrict flow in at least one of respective fluidlines connecting the at least two fluid sources to the pump inlet. Acontroller may be operatively associated with the valve device forcontrolling positional movement of the valve device actuator. A patientinterface device, such as a catheter as an example, may be associatedwith an outlet of the pump. The valve device actuator is generallyadapted to restrict the flow in at least one of the respective fluidlines such that an incremental positional change in valve deviceactuator position provides a substantially linear change in fluidmixture ratio of the fluids from the at least two fluid sources to thepump inlet.

The fluids may comprise at least contrast media and a diluent such assaline. The valve device actuator may be adapted to simultaneously atleast partially restrict flow in each of the respective fluid lines. Inone embodiment, the pump comprises a positive displacement pump, forexample, a multi-chamber piston pump. In another embodiment, the pumpcomprises a peristaltic pump. The respective fluid lines may havedifferent diameters. The respective fluid lines may comprisecompressible tubing, and the valve device may comprise a pinch valve andthe valve device actuator may comprise a pinch block adapted to restrictflow in at least one of the respective fluid lines via compression ofthe compressible tubing. Movement of the pinch block may be effected bya servomotor. The respective fluid lines may be joined via a branchconnector having an outlet in fluid connection with the pump inlet. Aflow meter may be associated with at least one of the respective fluidlines. The controller may effect positional change of the valve deviceactuator at least in part based on feedback from the flow meter.

Another aspect disclosed herein relates to a method for mixing anddelivering fluids such as contrast media and a diluent such as saline toa patient. Such a method generally includes providing a joining fluidpath connecting at least two fluid sources to an inlet to a pump,providing a valve device including a valve device actuator in the fluidpath upstream of the pump, and restricting the flow in at least one ofthe respective fluid lines with the valve device actuator. The valvedevice actuator is generally adapted to restrict flow in at least one ofrespective fluid lines connecting the at least two fluid sources to thepump inlet. The flow is restricted in at least one of the respectivefluid lines by the valve device actuator such that an incrementalpositional change in valve device actuator position provides asubstantially linear change in fluid mixture ratio of the fluids fromthe at least two fluid sources to the pump inlet.

The fluids may again comprise contrast media and a diluent such assaline. Another feature of the method relates to associating a patientinterface device, such as a catheter as an example, with an outlet ofthe pump. In one alternative, the valve device actuator simultaneouslyat least partially restricts flow in each of the respective fluid lines.A further feature of the method relates to associating a flow meter withat least one of the respective fluid lines. In one embodiment, the pumpcomprises a positive displacement pump. In another embodiment, the pumpcomprises a peristaltic pump. The respective fluid lines may havedifferent diameters. As noted hereinabove, the respective fluid linesmay comprise compressible tubing, and the method may further comprise atleast partially compressing the compressible tubing of at least one ofthe respective fluid lines with the valve device actuator to restrictflow. In one embodiment, the valve device may comprise a pinch valve andthe valve device actuator may comprise a pinch block adapted to restrictflow in at least one of the respective fluid lines via compression ofthe compressible tubing. A flow meter may be associated with at leastone of the respective fluid lines and the method may further comprise acontroller effecting positional change of the valve device actuator atleast in part based on feedback from the flow meter.

Further details and advantages will become clear upon reading thefollowing detailed description in conjunction with the accompanyingdrawing figures, wherein like parts are identified with like referencenumerals throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a fluid delivery system wherein two fluidsmay be delivered through use of two pumps to a patient.

FIG. 2 is a schematic view of a fluid delivery system whereinmulti-fluids may be delivered to a patient through use of a single pump.

FIG. 3 is a schematic view of an embodiment of a system capable ofcontrolled proportional mixing of fluids and continuous or intermittentdelivery thereof to a patient.

FIG. 4 is a perspective view of a portion of the system shown in FIG. 3showing a pump and a valve device of the system.

FIG. 5 is a plan view of the valve device provided in the system ofFIGS. 3-4.

FIG. 6 is a front and partial cross-sectional view of the valve deviceof FIG. 5.

FIG. 7 is a graphical representation of contrast medium concentration asa function of position of the valve device of FIGS. 5-6.

FIG. 8 is a perspective view of an embodiment of a mixing stopcock valvehaving applications in mixing two (or more) fluids.

FIG. 9 is a front view of the mixing stopcock of FIG. 8.

FIGS. 10A-10E are respective cross-sectional views of the mixingstopcock valve of FIGS. 8-9 showing various operational states of thevalve.

FIG. 11 is a schematic view of a variation of the fluid delivery systemof FIG. 2 incorporating a controlled mixing stopcock valve pursuant toFIGS. 8-10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of the description hereinafter, spatial orientation terms,if used, shall relate to the referenced embodiment as it is oriented inthe accompanying drawing figures or otherwise described in the followingdetailed description. However, it is to be understood that theembodiments described hereinafter may assume many alternative variationsand configurations. It is also to be understood that the specificdevices illustrated in the accompanying drawing figures and describedherein are simply exemplary and should not be considered as limiting.

FIG. 1 illustrates an exemplary system 10 for delivering contrast mediaand a diluent, such as saline, to a patient in a sequential orsimultaneous manner via the use of two pump platforms. While system 10is described in the context of the delivery of contrast and saline, forexample, to a patient, system 10 may be applicable for situations whereit is desired to supply any two fluids to a patient intravenously. Itwill be further appreciated that system 10 may be readily expanded todeliver multi-fluids (e.g., more than two fluids) to a patient. In theillustrated and non-limiting example, contrast media of similar ordifferent concentrations is contained in respective conventionalcontainers 12, 14. Respective and optional delivery reservoirs 16, 18are associated with contrast containers 12, 14. A contrast fluid path 20joins or connects the respective contrast reservoirs 16, 18 to a manualor automatic selector valve 22 provided in contrast fluid path 20.Contrast fluid path 20 includes a first input line 24 and a second inputline 26 connecting the respective reservoirs 16, 18 to first and secondinput ports 28, 30, respectively, to selector valve 22. An output port32 of selector valve 22 is associated with or connected to a first pump34 and, in particular, an inlet port 36 of first pump 34. First pump 34may be of conventional design such as the positive displacement,multi-piston pump disclosed in U.S. Pat. No. 6,197,000 to Reilly et al.incorporated herein by reference. Motive forces to operate first pump 34are provided by a pump servomotor 38 and pump drive 40. Outlet port 42of first pump 34 is associated or connected to a patient P via patientfluid path 44 and the output from first pump 34 to patient P iscontrolled by interposing a stopcock 46 in patient fluid path 44.Stopcock 46 has an input port associated with the outlet port 42 offirst pump 34 and further includes an outlet port associated with awaste reservoir 48. Other features of stopcock 46 are describedhereinafter.

Another portion of system 10 is a diluent delivery portion 50 wherein adiluent such as saline is provided in a conventional IV bag typecontainer 52. A second pump 54, which is typically identical to firstpump 34, has an outlet 55 connected to the patient fluid path 44 viastopcock 46 to provide saline solution to patient P and/or saline flushto fluid path 44. Second pump 54 is provided with its own pumpservomotor 56 and pump drive 58. Diluent container 52 is connected via adiluent fluid path 60 to a second input port on stopcock 46 so as toprovide diluent supply and flush to patient fluid path 44. As shown inFIG. 1, stopcock 46 has a first input port A associated outlet port 42of pump 46 34, a second input port B associated with associated outletport 55 of second pump 54, a first outlet port C associated with patientfluid path 44, and a second outlet port D associated with wastereservoir 48. Selector valve 22 may be automatically or remotelyoperated via control of a valve servomotor 62 and associated valve drive64 and may be, for example, an automated stopcock. If desired, stopcock46 may be automated in a similar manner to selector valve 22. Acontroller (not shown) may be provided to automate operation of system10 via control of pump servomotors 38, 56 and valve servomotor 62.

In operation, selector valve 22 may be operated to select the contentsof one of the two provided contrast-containers 12, 14 which allows pump34 to extract the selected contrast medium via contrast fluid path 20and selector valve 22 and deliver the selected contrast medium topatient fluid path 44 via stopcock 46. Saline may be delivered topatient fluid path 44 via stopcock 46 by operation of second pump 54 anddiluent fluid path 60. Pumps 34, 54 may be alternately operated tosequentially supply selected contrast medium and saline to patient fluidpath 44. Alternatively, both pumps 34, 54 may be operatedsimultaneously, with mixing of the selected contrast medium and salineoccurring in the patient fluid path 44 and/or in stopcock 46. Stopcock46 is desirably configured to permit at least partial simultaneous fluidcommunication to be present between pump outlet 42 of first pump 34 andpump outlet 55 of second pump 54 with patient fluid path 44 to permitsimultaneous delivery of both contrast medium and saline to patientfluid path 44.

Typically, mixing of the selected contrast media and saline to achieveany desired proportional mixture of these fluids is accomplished bycontrolling the flow rate delivered by the respective pumps 34, 54.However, this is also a disadvantage with system 10 as two separatepumps 34, 54 must be operated and, further, their operations coordinatedto deliver a desired, proportioned mixture of contrast and saline topatient fluid path 44. This arrangement is similar to that disclosed inU.S. Pat. No. 3,935,971 to Papoff et al. discussed previously, whereinthe operating speeds of two peristaltic pumps must be controlled andcoordinated to obtain a desired proportional mixture of two fluids. Insystem 10, similar control of pumps 34, 54 is necessary to obtain adesired mixture ratio or proportional mixture of contrast and saline.The pump control aspects of U.S. Pat. No. 3,935,971 to Papoff et al.applicable to the control of pumps 34, 54 are incorporated herein byreference.

Mixing of the selected contrast medium and saline may also beaccomplished with use of a “mixing” stopcock valve for stopcock 46, suchas disclosed in U.S. Pat. No. 3,957,082 to Fuson et al., incorporated byreference previously (but as a two-fluid version of this valve), ratherthan by operational control of pumps 34, 54. However, a preferred mixingstopcock valve 300 particularly suitable for this application isdiscussed herein in connection with FIGS. 8-10 which accounts forupstream pressure and/or viscosity differences between contrast mediumand saline which is not a feature or consideration of the Fuson et al.mixing stopcock. It is noted that selector valve 22 may also be a mixingstopcock valve as disclosed in the Fuson et al. patent (but as atwo-fluid version of this valve) if it is desired to mix the contents ofcontrast containers 12, 14 in a preset or “fixed” proportional mixtureprior to delivering this contrast mixture to first pump 34. However,again, such a known mixing stopcock valve as disclosed by Fuson et al.does not account for upstream pressure and/or viscosity differenceswhich may be present between the contrast media present in contrastcontainers 12, 14 as does the mixing stopcock valve 300 illustrated inFIGS. 8-10 and discussed herein. Use of mixing stopcock valve 300 insystem 10 permits pumps 34, 54 to operate at the same or substantiallythe same speeds, which proportional mixing being accomplished by valve300, as described herein.

FIG. 2 illustrates a variation of system 10 referred to as system 10awhich eliminates second pump 54 by directly connecting diluent container52a via diluent fluid path 60a to a third input port 66a of selectorvalve 22a. Accordingly, contrast media from contrast containers 12a, 14aand saline from diluent container 52a are each connected through singleselector valve 22a so that any one of these three fluids may be providedvia pump 34a to patient fluid path 44a. However, in this specificconfiguration, typically only one fluid at a time may be provided topatient P via patient fluid path 44a providing only the ability toprovide sequential flow of the fluids to patient P. As a result,modified system 10a lacks the ability to mix contrast media and diluentsuch as saline, proportionally or otherwise, and deliver a mixture ofcontrast and diluent to patient P without modification to selector valve22a. While it may be possible to replace selector valve 22a with themixing stopcock valve disclosed in U.S. Pat. No. 3,957,082 to Fuson etal. which allows an operator to “dial-in” a selected fluid choice or apreset proportional mixture of fluids (e.g., a 50%-50% mixture), theFuson et al. stopcock valve does not account for upstream pressureand/or viscosity differences, as noted previously, which may be presentbetween the fluids entering such a stopcock as does mixing stopcockvalve 300 described herein in connection with FIGS. 8-10. In general,the conventional mixing stopcock valve disclosed by Fuson et al. islimited in application to permitting full fluid flow from a first fluidsources, full fluid flow from a second fluid source, or at most a fewpreset or “fixed” proportional mixture settings for the two fluids to bedelivered to a patient and, hence, does not permit a full range of fluidmixture ratios or proportions to be delivered to a patient as providedby the system 100 discussed herein in connection with FIGS. 3-7. Theoperational control of pumps 34, 54 in system 10 discussed previouslymay provide a fuller range of fluid mixture ratios or proportions to bedelivered to a patient but respective operational control of pumps 34,54 is difficult in practice to achieve with accuracy particularly whenthe two fluids have significantly different viscosities as is the casewith contrast media and saline. It will be clear that, if desired,additional fluid sources may be provided in system 10a with each havingan additional input line to selector valve 22a.

FIG. 3 is a schematic representation of an embodiment of a system 100capable of controlled proportional mixing of fluids and further capableof intermittent or continuous delivery of a proportional mixed fluid toa patient. In one example, the fluids may be contrast media and salinewhich may be proportionally mixed in any desired mixture ratio anddelivered either intermittently or continuously to a patient undergoingmedical radiographic imaging procedure. System 100 is described forexemplary purposes in the context of contrast media and saline and thecontrolled proportional mixing and delivery thereof to a patient P toexplain the features of the invention. However, this specificapplication or explanation should not be considered as precluding theuse of system 100 in other situations. Generally, system 100 is suitablefor use in any situation where it is desired to mix two (or more) fluidsin a controlled proportional manner and deliver such as a mixed fluidintermittently or continuously to a patient undergoing a medicalprocedure involving intravenous fluid infusion, such as the proportionalmixing of a drug with a diluent such as saline as an example. A fullrange of proportional mixtures between two (or more) fluids may beobtained as outputs to the patient P as described herein. Moreover, itis explicitly noted that the principle of operation of system 100 may beexpanded to multi-fluids (e.g., three or more) if desired. System 100has similar architecture to systems 10, 10a discussed previously withcertain alterations and additions as described herein. Accordingly, inview of the foregoing, it is expressly noted that system 100 is notlimited to just two fluids and is specifically not limited to contrastand saline as fluids which may be handled by system 100.

In system 100, contrast media of similar or different concentrations iscontained in respective conventional containers 112, 114. Respective andoptional contrast reservoirs 116, 118 are associated with contrastcontainers 112, 114. A contrast fluid path 120 joins or connects therespective reservoirs 116, 118 to a manual or, desirably, automaticselector valve 122 provided in contrast fluid path 120. Contrast fluidpath 120 includes a first input line 124 and a second input line 126connecting the respective contrast reservoirs 116, 118 to first andsecond input ports 128, 130 to selector valve 122. An output port 132 ofselector valve 122 is associated with or connected to a pump 134 and, inparticular, an inlet port 136 of pump 134 via a joining fluid path 200which is associated with an intervening valve device 210. The details ofjoining fluid path 200 and valve device 210 are described hereinafter.

Pump 134 may be of conventional design such as the positivedisplacement, multi-piston pump disclosed in U.S. Pat. No. 6,197,000 toReilly et al., previously incorporated herein by reference. Motiveforces to operate pump 134 are provided by a pump servomotor 138 andpump drive 140. An outlet port 142 of pump 134 is associated orconnected to a patient P via patient fluid path 144 and the output frompump 134 to patient P is controlled by interposing a stopcock 146 inpatient fluid path 144. Stopcock 146 has an input port associated withthe outlet port 142 of pump 134 and further includes an outlet portassociated with a waste reservoir 148. Peristaltic pumps may also beused as in place of the positive displacement pump disclosed by Reillyet al. Peristaltic pumps are well-known in the medical filed fordelivery fluids to patients.

Another portion of system 100 is a diluent delivery portion 150 whereina diluent such as saline is provided in a conventional IV bag typecontainer 152. Diluent container 152 is connected via joining fluid path200 to inlet port 136 of pump 134. Valve device 210 is operable tocontrol the flow of contrast and saline in joining fluid path 200 toachieve desired proportional mixing of contrast and saline entering pump134 via pump inlet 136. As shown in FIG. 3, stopcock 146 has a firstinput port A associated outlet port 142 of pump 136, and first andsecond outlet ports C, D associated with patient fluid path 144 andwaste reservoir 148, respectively. Selector valve 122 may beautomatically or remotely operated via control of a valve servomotor 162and associated valve drive 164. If desired, stopcock 146 may be anautomated stopcock, for example, and automated in a similar manner toselector valve 122. Selector valve 122 may also be a “mixing” stopcockvalve as disclosed in the Fuson et al. patent described previously (buta two-fluid version of this valve), if it is desired to mix the contentsof contrast containers 112, 114 in preset or “fixed” proportions orratios prior to delivering this contrast mixture to joining fluid path200. As noted previously, the Fuson et al. “mixing” stopcock valve doesnot account for upstream pressure and/or viscosity differences which maybe present between the contrast media present in contrast containers112, 114 as does mixing stopcock valve 300 discussed herein inconnection with FIGS. 8-10.

Referring further to FIG. 4-7, further details of system 100 includingjoining fluid path 200 and valve device 210 are shown. Joining fluidpath 200 comprises a first fluid branch or line 202 to conduct selectedcontrast medium to the pump inlet 136 of pump 134 and a second fluidbranch or line 204 to conduct diluent (typically saline) to the pumpinlet 136 of pump 134. The first and second fluid lines 202, 204 arejoined via a joining connector 206, such as a conventional T-connectoror a conventional Y-connector as shown. Joining connector 206 is influid communication with pump inlet 136 to provide selected contrastmedium and saline as a mixture to pump 134 which delivers this fluidmixture to patient fluid path 144 via stopcock 146. Desirably, first andsecond fluid lines 202, 204 are conventional medical tubing made of aflexible and resiliently compressible material, such as medical gradesilicone tubing. As shown in FIG. 5, each of the first and second fluidlines 202, 204 comprises a portion or length L associated with valvedevice 210 so that valve device 210 is operable to act upon this lengthL of the first and second fluid lines 202, 204 to restrict fluid flow inone or both of the first and second fluid lines 202, 204.

As best illustrated in FIG. 6, it will be apparent that first and secondfluid lines 202, 204 may have different diameters with the second“diluent” fluid line 204 having a smaller diameter than the first“contrast” fluid line 202. This illustration is relevant for contrastmedia and saline as the fluids to be mixed in system 100 and should notbe considered as limiting or exhaustive. The diameters of fluid lines202, 204 may be set as necessary to achieve controlled proportionalmixing of two fluids to deliver a desired mixture ratio of these fluidsto pump 134, as described herein. In the case of contrast and saline,which have significantly different viscosities, diluent fluid line 204is typically smaller in diameter than contrast fluid line 202 as salinehas a lower viscosity than typical contrast media. However, in the casewhere system 100 is used to mix two fluids of similar viscosity andupstream head pressure, the diameters of fluid lines 202, 204 may beroughly or exactly equal. Generally, the fluid associated with fluidline 202 in system 100 has a higher viscosity than the fluid associatedwith fluid line 204 in system 100 and this generally translates intofluid line 202 having a larger diameter than fluid line 204 to achieveproportional mixing in a “linear” manner pursuant to the discussionherein.

In one embodiment, valve device 210 may be a dual pinch valve thatincludes a valve actuator 212 operably associated with the first andsecond fluid lines 202, 204 associated with valve device 220. In theillustrated configuration, valve device 210 comprises a base 214 havingtwo laterally disposed, spaced apart, and upstanding sidewalls 216. Thebase 214 comprises an upstanding dividing portion 218 in an area 220defined between sidewalls 216. Sidewalls 216 and dividing portion 218define a pair of generally parallel channels 222, 224 which accommodatefirst and second fluid lines 202, 204, respectively. In particular,channels 222, 224 accommodate the length L of the first and second fluidlines 202, 204 which are to be operably engaged by valve actuator 212 asdescribed herein. In one embodiment, valve actuator 212 comprises apinch block 226 which is movable laterally or horizontally in area 220to apply compressive forces to one or both of the first and second fluidlines 202, 204. Pinch block 226 is movable in a lateral, side-to-sidemanner in area 220 by a coupled drive mechanism 228 and servomotor 230.A feature of the configuration of valve device 210 relates to pinchblock 226 being appropriately sized, configured, and positioned in area220 such that both the first and second fluid lines 202, 204 are in apartial state of compression in channels 222, 224 and, thereby, provideflow restriction to the respective fluids passing through the first andsecond fluid lines 202, 204, namely contrast and saline. Such mutualcompression of fluid lines 202, 204 aid in “linear” proportional mixingof contrast and saline during operation of system 100 as describedherein. A flow meter 232 is associated with at least one of the fluidlines 202, 204, typically the second “saline” fluid line 204 to measureflow rate of saline to pump inlet 136 of pump 124. Moreover, checkvalves 234 may be provided in fluid lines 202, 204 to prevent backflowto contrast media containers 112, 114 and diluent container 152 duringoperation of system 100. A control device or controller 240 is providedin system 100 to control operation of the system 100. As such,controller 240 is electronically connected for two-way communicationwith at least pump servomotor 138 and pinch block servomotor 230 used tocontrol movement pinch block 226, and desirably in two-way communicationwith flow meter 232 and selector valve servomotor 162, although flowmeter 232 may be adapted just to provide saline flow rate information tocontroller 240.

In operation, system 100 in the exemplary embodiment outlined in theforegoing delivers a mixture of contrast and saline in any desiredproportion or mixture ratio and, with appropriate control of pump 134,this proportional fluid mixture may be delivered to patient Pcontinuously or intermittently as desired. Moreover, system 100 may becontrolled such that for incremental or discrete changes in position ofvalve actuator 212, substantially linear fluid mixture ratio changesbetween contrast and saline are obtained at the pump inlet 136 which isthen delivered by pump 134 via stopcock 146 to patient fluid path 144and patient P. In system 100, flow rate of saline is determined or knownas an input to controller 240 from flow meter 232 and total output flowfrom pump 134 is a known quantity as a positive-displacement type pump(e.g., operational feedback from pump servomotor 138). From these inputsto controller 240, the amount of contrast needed for a desiredproportional mixture at pump inlet 136 may be calculated by controller240. Controller 240 may then control positioning of pinch block 226 viapinch block servomotor 230 based on the feedback from flow meter 232 andpump servomotor 138. Since flow rate of contrast and saline in fluidlines 202, 204 relates to pressure drop in each line and this changeswith viscosity of the respective fluids, differential diametrical sizingof fluid lines fluid lines 202, 204 may be used to provide a generallylinear mixing ratio response with positional change of pinch block 226.In other words, controller 240 may continuously change lateral positionof pinch block 226 based on inputs (feedback) from flow meter 232 andpump servomotor 138 to provide more or less compression to one or theother of contrast and saline fluid lines 202, 204 which are pre-selectedin advance such that this changing compression results in a generallylinear mixture ratio response change at pump inlet 136. Accordingly,this result is achieved by sizing fluid lines 202, 204 appropriately andfeedback control of pinch block 226 in area 220 such that for eachincremental or discrete change in horizontal, side-to-side position ofpinch block 226 in area 220, one and, typically, both of the first andsecond fluid lines 202, 204 will undergo different degrees ofcompression (more or less) in channels 222, 224 and, therefore,restriction and as a result the concentration of contrast media enteringpump inlet 136 changes by substantially a directly proportional or“linear” amount. This directly proportional or linear relationshipbetween pinch block 226 position and contrast medium concentration isreflected in FIG. 7 illustrating a specific implementation or example ofoperation of system 100.

In the specific and non-limiting example resulting in the graphicalmodel shown in FIG. 7, first or contrast fluid line 202 may have adiameter of 0.187 in and second or saline fluid line 204 may have adiameter of 0.062 in. First and second fluid lines 202, 204 are disposedin respective channels 222, 224. Valve device actuator 212, namely,pinch block 226 is disposed in area 220 such that pinch block 226 atleast partially compresses both fluid lines 202, 204 restricting fluidflow of contrast and saline therein, respectively. Flow rate of salineis determined or known from flow meter 232 and total output flow frompump 134 is a known quantity as described previously. As furtherdescribed previously, change in lateral or side-to-side position ofpinch block 226 is controlled by drive mechanism 228 and accompanyingservomotor 230. A software algorithm is desirably provided in a controldevice or controller 240 to control with precision the movement of pinchblock 226 in area 220. Such controlled movement of pinch block 226controls with generally equal precision the amount of compression orrestriction in one or both of fluid lines 202, 204. FIG. 7 illustratesthat with appropriate relative sizing between fluid lines 202, 204 andfeedback control of pinch block 226, incremental positional changes ofpinch block 226 result in substantially directly proportional or linearchanges in contrast concentration to pump inlet 136 of pump 134 over arange of fluid flows. Accordingly, if it is desired to adjust contrastconcentration down or up, movement of pinch block 226 permits additionalor less saline pass through valve device 210. For example, if additionalsaline is required to adjust the desired ratio, pinch block 226 iscontrolled in response to provide less restriction or compression ofsaline fluid line 204 while further restricting or compressing contrastfluid line 202. While the foregoing operation of system 100 wasdescribed in a manner indicating that both fluid lines 202, 204 are eachin partial compression during operation of system 100, it will be clearto those skilled in the art that this need not always be the case andthat the system 100 may be configured such that only one fluid line iscompressed at a time during operation of system 100.

In the foregoing non-limiting example, the relationship between thechange in position of pinch block 226 and the contrast mediumconcentration has been described as substantially linear. However, itshould be noted that nonlinear relationships can be obtained byvariations of system 100. For example, for some incremental changes inposition of pinch block 226, the concentration of contrast medium maychange exponentially or by some other nonlinear factor. For example, ifthe position changes by an amount x, the concentration may increase byan amount proportional to x^(n). Such nonlinear relationships may beachieved depending upon several factors including the particular sizesand configurations of the components of system 100, fluid viscosities ofthe fluids involved, upstream pressure differential, and flow ratesutilized.

While the foregoing system 100 and its operation was described withreference to two specific fluids, namely, contrast and saline, thisshould not be considered as limiting as noted previously. Additionally,system 100 may be expanded to accommodate additional fluids beyond justthe two-fluid application discussed hereinabove. This may beaccomplished, for example, by adding a third fluid source and anaccompanying third flow path in joining flow path 200 passing throughvalve device 210 and configuring valve device 210 and, namely, valveactuator 212 to act upon this third or additional flow path. In such asituation, pinch block 226 may be sized and configured to includedepending portions that can simultaneously compress or pinch two or moreof the multi-flow flow paths. For example, in a three-fluidmodification, an additional “middle” side wall 216 could be provided tooperate on a “middle” flow path so that the modified pinch block 226 cancompress it in addition to one of the other two paths. In this manner,two of the three flow paths may be restricted while the other isunrestricted. Alternatively, two separately controlled pinch blocks 226may be used on respective sides of the “middle” flow path so that thepinching is independently performed by each pinch block 226, allowingthe two pinch blocks to move in opposite directions. Moreover, while itwas indicated in the foregoing that both fluid lines 202, 204 of joiningflow path 200 are each typically at least partially compressed orrestricted during operation of valve device 210 and valve actuator 212,fluid lines 202, 204 and valve device 210 and, namely, valve actuator212 may be designed such that only one of these fluid lines 202, 204needs to compressed at any given time to achieve proportional fluidmixing and desirably linear proportional fluid mixing while the otherfluid line remains in an uncompressed or normal state.

Referring to FIGS. 8-10, a “mixing” stopcock valve 300 is illustratedwhich may be used in the foregoing systems 10, 10a, 100 in the specificlocations/applications identified hereinabove. Mixing stopcock valve 300is adapted to provide proportional mixing of two (and potentiallymultiple fluids) which have differing upstream pressures and/orviscosities to realize, according to one feature, accurate proportionalmixtures of the two fluids. As described previously, mixing-typestopcock valves are generally known, for example, from Fuson et al.However, the mixing-type stopcock valve described in Fuson et al.assumes that upstream pressure and/or viscosity differences arenon-existent or minimal between the two or more fluids being mixed inthis valve. In the case of contrast media and saline as examples,viscosity of the two fluids differs substantially such that if the Fusonet al. valve were used with contrast and saline, the preset or fixedproportional mixtures, for example, a 50%-50% mixture in one selectionposition, designed to result from this valve will not occur with anyaccuracy. The mixing stopcock 300 of FIGS. 8-10 overcomes thislimitation with the prior art as differences in upstream pressure and/orviscosity are accounted for in the structure of the valve.

Mixing stopcock valve 300 comprises a stopcock body 302 formed ofplastic material, desirably a medical grade plastic material. A stopcockactuator 304 is disposed in a valve chamber 306 defined by stopcock body302. Additionally, stopcock body 302 defines a plurality of input ports,namely, a contrast input port 308 and a saline input port 310 in theillustrated embodiment. While mixing stopcock valve 300 is describedwith reference to contrast and saline for illustrative purposes only, itwill be clear that mixing stopcock 300 valve is suitable forapplications where it is desired to mix any two (or possibly more)fluids of differing upstream pressure and/or viscosity. Stopcock body302 further defines an outlet port 312. Inlet ports 308, 310 and outletport 312 may be configured as luer-type connectors as illustrated. Inletports 308, 310 comprise contrast and saline inlet ports 308, 310 in thepresent example.

Stopcock actuator 304 defines a generally T-shaped internal conduit 314.Internal conduit 314 includes a first conduit portion 316 and a secondconduit portion 318 of generally similar or equal diameter, and furtherdefines a third conduit portion 320 of reduced diameter relative to thediameters of first and second conduit portions 316, 318. The relativedifference in diameters between third conduit portion 320 and first andsecond portions 316, 318 accounts for upstream pressure and/or viscositydifferences between the fluids to be conducted through stopcock valve300 as in the present case involving contrast and saline. Relativediameter sizing between third conduit portion 320 and first and secondportions 316, 318 to account for upstream pressure and/or fluidviscosity differences is readily within the skill of those skilled inthe art.

FIG. 10A-10E illustrate operation of mixing stopcock 300 wherein thevarious positions of stopcock actuator 304 permit full contrast, fullsaline, or a mixture of contrast and saline to be delivered to outletport 312. In FIG. 10A, an “off” or no-flow position of stopcock valve300 is illustrated, wherein stopcock actuator 304 is positioned suchthat internal conduit 314 is unaligned with inlet ports 308, 310 andoutlet port 312 thereby blocking flow into or from internal conduit 314.In FIG. 10B, stopcock actuator 304 is positioned such that first andsecond conduit portions 316, 318 of internal conduit 314 are alignedwith contrast port 308 and outlet port 312, respectively, to permitdelivery of contrast only to outlet port 312. In FIG. 10C, stopcockactuator 304 is positioned such that second conduit portion 318 andreduced diameter third conduit portion 320 are aligned are aligned withsaline port 310 and outlet port 312, respectively, to permit delivery ofsaline only to outlet port 312. It is noted that due to the lowerviscosity of saline, the reduced diameter third conduit portion 320permits a similar flow rate of saline to result in outlet port 312 asobtained in the contrast-only setting shown in FIG. 10A. In FIG. 10D,stopcock actuator 304 is positioned such that first conduit portion 316and reduced diameter third conduit portion 320 are aligned are alignedwith saline port 310 and contrast port 308, respectively, to permitdelivery of an accurate 50%-50% mixture of saline and contrast to outletport 312 via second conduit portion 318 of internal conduit 314. In FIG.10D, by aligning the reduced diameter third conduit portion 320 withcontrast port 308 more restriction is present to the high viscositycontrast medium while less restriction is present to the lower viscositysaline passing through saline port 310 and first conduit portion 316.These relative differences in restriction of flow due to diameterdifferences results in the combining of contrast and saline in anaccurate 50%-50% mixture. As shown in FIGS. 8-9, the contrast onlysetting of FIG. 10B is represented by a “C” tab mark on stopcock body302, the saline only setting of FIG. 10C is represented by a “S” tabmark on stopcock body 302, and other proportional mixtures between fullcontrast and full saline are denoted by tab marks 322 on stopcock body302. For example, tab mark 322(2) corresponds to a 50%-50% mixture ofcontrast and saline (FIG. 10D), while tab mark 322(1) corresponds to a75% saline-25% contrast mixture and tab mark 322(3) corresponds to a 75%contrast-25% saline mixture.

FIG. 10E illustrates a further aspect of mixing stopcock 300 wherein a“custom mix” of contrast and saline may be obtained. Gradationsrepresenting these custom proportional mixtures may be visually andtactilely provided on the stopcock body 302 by providing a plurality oftab marks similar to tab marks 322 discussed previously between tab mark“S” and tab mark “C” as an example. In FIG. 10E, stopcock actuator 304is positioned such that first conduit portion 316 is in fluidcommunication but not aligned directly with saline port 310 resulting inrestricted flow of saline, and reduced diameter third conduit portion320 is in fluid communication but not aligned directly with contrastport 308 resulting in restricted flow of contrast. As such, a specificproportional mixture of contrast and saline is delivered to outlet port312 when the stopcock actuator 304 is in the orientation shown in FIG.10E.

As stopcock actuator 304 is rotated clockwise, the flow restrictionbetween third conduit portion 320 and contrast port 308 decreases and,concurrently, the flow restriction between first conduit portion 316 andsaline port 310 also decreases. Since the diameter of third conduitportion 320 is less than that of first conduit portion 316, the rate offlow increases faster through third conduit portion 320 than throughfirst conduit portion 316. This result occurs because a largerpercentage of third conduit portion 320 comes into increased fluidcommunication with contrast port 308 more quickly than occurs betweenfirst conduit portion 316 and saline port 310 through the same angle ofrotation of stopcock actuator 304. Because the flow rate of contrastincreases faster and more fluid area is opened to flow more quickly thanon the saline “side” as stopcock actuator 304 is rotated clockwise, theconcentration of contrast medium flowing through second conduit portion318 increases with clockwise rotation of the stopcock actuator 304. Oncethird conduit portion 320 first comes into substantially unrestrictedfluid communication with the contrast port 308 (but still less than adirect alignment between third conduit port 320 and contrast port 308 asin FIG. 10D), some flow restriction between first conduit portion 316and saline port 310 is still present. Thus, maximum concentration ofcontrast will occur when the third conduit portion 320 first comes intosubstantially unrestricted fluid communication with contrast port 308.This maximum concentration is greater than 50% because the maximumamount of contrast is able to flow though third conduit portion 320, butfirst conduit portion 316 is not fully aligned with saline port 310, asin the orientation shown in FIG. 10D, and some flow restriction is stillpresent. As stopcock actuator 304 is rotated further clockwise, theconcentration of contrast decreases as the saline flow restriction isremoved and more saline is able to flow through first conduit portion316. Eventually, first conduit portion 316 is fully aligned with salineport 310 as in the orientation shown in FIG. 10D, making the making themixture flow present in outlet port 312 a 50% contrast/50% salinemixture.

As the stopcock actuator 304 is rotated either clockwise orcounterclockwise from the orientation shown in FIG. 10D, the flow ofsaline will initially decrease as the flow of contrast remains the same.This is again due to the diameter differences between third conduitportion 320 and first conduit portion 316, whereby first conduit portion316 is almost immediately subject to flow restriction while thirdconduit portion 320 remains substantially unrestricted. Thus,concentration of contrast will again increase to greater than 50%. Oncethird conduit portion 320 begins to close as stopcock actuator 304 iscontinued to be rotated either clockwise or counterclockwise, the rateof flow decreases faster through third conduit portion 320 than throughfirst conduit portion 316 and the concentration of contrast in themixture again falls. This result is again due to the diameterdifferences between the third conduit portion 320 and first conduitportion 316. At some point in the rotation of stopcock actuator 304,flow of saline also ceases as the stopcock actuator 304 is placed in the“OFF” position illustrated in FIG. 10A.

The rate at which contrast medium concentration increases with rotationof stopcock actuator 304 depends upon the relative shapes (e.g.,diameters) and relative cross-sectional areas of first conduit portion316 and third conduit portion 320 open to fluid flow. These relativeshapes and cross-sections may be sized and configured such that thepercentage of contrast medium will vary in a substantially linearproportion to rotation of stopcock actuator 304. In other words, mixingstopcock 300 may be configured such that for a known angle of rotationof stopcock actuator 304, a substantially directly proportional increaseor decrease in concentration of contrast medium is obtained in outletport 312. For example, rotating stopcock actuator 304 of mixing stopcock300 can cause the concentration of contrast in the fluid mixture inoutlet port 312 to range from substantially 0% in the fluid mixture to apercentage greater than 50%, which can be as much as about 80-90% in thefluid mixture. The rate of change in fluid mixture ratio or proportionmay be substantially linear or directly proportion between the foregoingminimum and maximum contrast concentrations.

FIG. 11 illustrates a system 10b which is a variation of system 10a ofFIG. 2 and applies the advantages of the “custom mix” application ofFIG. 10E to a fluid delivery system comprising two fluids of differingviscosity, such as contrast and saline as an example. The details ofsystem 10b are generally similar to system 10a except that diluentdelivery portion 50a is deleted from system 10b and one of contrastcontainers 12a, 14a, container 14a as an example, is now filled withdiluent such as saline and identified in FIG. 11 with referencecharacter 52b for consistency with the foregoing disclosure.Accordingly, fluid path 20b carries both contrast and saline in thisembodiment. Additionally, selector valve 22a is replaced with mixingstopcock valve 300, as illustrated, having the features describedhereinabove and particularly has the features described in connectionwith FIG. 10E, namely a “custom mix” capability. Moreover, stopcockvalve 300 may be automated in a similar manner to valve 22a. With thepositioning of stopcock valve 300 in system 10b, custom proportionalmixing, which changes in a substantially linear or directly proportionalmanner, may be accomplished between contrast medium from container 12band diluent (e.g., saline) from container 52b which are intended to beexemplary and non-limiting examples of two fluids that may be mixed anddelivered by system 10b. Pump 34b may thereby deliver a customproportional mixture of fluids to patient fluid path 44b via stopcock46b. A controller 240b similar to controller 240 described previouslymay be used to control operation of pump 34b via pump servomotor 38b andoperation of automatic stopcock valve 300 via valve servomotor 62b.Additionally, controller 240b receives saline flow rate data from flowmeter 232b associated with saline fluid path 50b and total flow data viaelectronic communication with pump servomotor 38b in a similar manner tothat described with respect to system 100 discussed hereinabove. As willbe clear from the foregoing discussion of controller 240 in system 100,controller 240b provides continuous input to valve servomotor 62b whichcontrols rotational positioning of stopcock actuator 304 to maintain orachieve a desired proportional “custom mix” of contrast and saline topump inlet 36b. As described previously, flow meter 32b and pumpservomotor 38b provide the feedback information or data to controller240b to allow controller 240b to make continuous rotational updates ofstopcock actuator 304 to maintain or achieve the desired proportional“custom mix” of contrast and saline to pump inlet 36b. In other words,controller 240b operates in an analogous manner to controller 240described previously but in system 10b rotational positional movement ofstopcock actuator 304 is used to achieve the desired result of directlyproportional or linear changes in contrast concentration to pump inlet36b of pump 34b over a range of fluid flows.

While embodiments of a system capable of capable of controlledproportional mixing and delivery of fluid mixtures to a patient and, inone particular application, the controlled proportional mixing ofcontrast medium with saline for delivery to a patient undergoing amedical imaging procedure was provided in the foregoing description,those skilled in the art may make modifications and alterations to theseembodiments without departing from the scope and spirit of theinvention. Accordingly, the foregoing description is intended to beillustrative rather than restrictive. The invention describedhereinabove is defined by the appended claims and all changes to theinvention that fall within the meaning and the range of equivalency ofthe claims are to be embraced within their scope.

The invention claimed is:
 1. A system for mixing and delivering fluids,comprising: a first fluid source configured to supply a first fluid; atleast a second fluid source configured to supply at least a secondfluid; a first fluid line in configured for fluid connection with the afirst fluid source for supplying a first fluid; at least a second fluidline in configured for fluid connection with the an at least secondfluid source for supplying at least a second fluid; a pump having aninlet and an outlet; and a mixing stopcock valve having a first inputport, at least a second input port, an outlet port, and a stopcockactuator, wherein the first input port is in fluid communication withthe first fluid line, the at least second input port is in fluidcommunication with the at least second fluid line, and the outlet portis in fluid communication with an the inlet of the pump, wherein thestopcock actuator comprises an internal conduit defining a first conduitportion, a second conduit portion, and a third conduit portion ofreduced diameter relative to the diameter of the first conduit portion,and wherein a positional change in the a position of the stopcockactuator provides a change in the a fluid mixture ratio of the first andat least second fluids delivered to a patient.
 2. The system as claimedin claim 1, wherein the first fluid and the at least second fluidcomprise at least contrast media and a diluent.
 3. The system as claimedin claim 1, wherein the stopcock actuator is adapted to simultaneouslyat least partially restrict flow in each of the fluid lines.
 4. Thesystem as claimed in claim 1, wherein the pump comprises a positivedisplacement pump.
 5. The system as claimed in claim 4, wherein thepositive displacement pump comprises a multi-chamber piston pump.
 6. Thesystem as claimed in claim 1, wherein the first fluid line has a firstdiameter, the at least second fluid line has an at least seconddiameter, and the first diameter differs from the at least seconddiameter.
 7. The system as claimed in claim 1, further comprising a flowmeter associated with at least one of the fluid lines.
 8. The system asclaimed in claim 1, wherein the pump comprises a peristaltic pump.
 9. AThe system as claimed in claim 1, further comprising: a controlleroperatively associated with the mixing stopcock valve for controllingthe positional movement change of the stopcock actuator; and a flowmeter associated with at least one of the fluid lines.
 10. The system asclaimed in claim 9, wherein the controller effects the positional changeof the valve stopcock actuator at least in part based on feedback fromthe flow meter.
 11. The system as claimed in claim 9, wherein the firstfluid and the at least second fluid comprise at least contrast media anda diluent.
 12. The system as claimed in claim 9, wherein the stopcockactuator is adapted to simultaneously at least partially restrict flowin each of the fluid lines.
 13. The system as claimed in claim 9,further comprising a patient interface device associated with the outletof the pump.
 14. The system as claimed in claim 9, wherein the pumpcomprises a positive displacement pump.
 15. The system as claimed inclaim 14, wherein the positive displacement pump comprises amulti-chamber piston pump.
 16. The system as claimed in claim 9, whereinthe first fluid line has a first diameter, the at least second fluidline has an at least second diameter, and the first diameter differsfrom the at least second diameter, or the first input port has a firstport diameter, the at least second input port has an at least secondport diameter, and the first port diameter differs from the at leastsecond port diameter.
 17. The system as claimed in claim 9, wherein thepump comprises a peristaltic pump.
 18. A method of mixing and deliveringfluids from a first fluid source and at least a second fluid sourceusing a fluid delivery system comprising a pump having an inlet and anoutlet, and a mixing stopcock valve having a first input port, at leasta second input port, an outlet port and a stopcock actuator comprisingan internal conduit defining a first conduit portion, a second conduitportion, and a third conduit portion of reduced diameter relative to thediameter of the first conduit portion, the method comprising: providingthe fluid delivery system having a first fluid line with a first end anda second end, and at least a second fluid line with a first end and asecond end; connecting the first end of the first fluid line to thefirst fluid source, and the first end of the at least second fluid lineto the at least second fluid source; connecting the second end of thefirst fluid line to the first input port of the mixing stopcock valve,and the second end of the at least second fluid line to the at leastsecond input port of the mixing stopcock valve; and connecting theoutlet port of the mixing stopcock valve to the inlet of the pump; and,wherein actuating the stopcock actuator such that to effect a positionalchange in the a position of the stopcock actuator provides effects achange in the a fluid mixture ratio of a first fluid and at least asecond fluid.
 19. The method as claimed in claim 18, further comprisingassociating a patient interface device with the outlet of the pump. 20.The method as claimed in claim 18, wherein the first fluid line has afirst diameter, the at least second fluid line has an at least seconddiameter, and the first diameter differs from the at least seconddiameter.
 21. The method as claimed in claim 18, further comprising:providing a flow meter associated with at least one of the fluid lines;and providing a controller adapted to effect the positional change ofthe stopcock actuator at least in part based on feedback from the flowmeter.
 22. A method of manufacturing a system for mixing and deliveringfluids, the method comprising: providing a first fluid line having afirst end configured for fluid connection with a first fluid source forsupplying a first fluid; providing at least a second fluid lineconfigured for fluid connection with at least a second fluid source forsupplying at least a second fluid; providing a pump having an inlet andan outlet; providing a mixing stopcock valve having a first input portconfigured for connecting to a second end of the first fluid line, atleast a second input port configured for connecting to a second end ofat least the second fluid line, and an outlet port configured forconnecting to the inlet of the pump; and providing a stopcock actuatoron the mixing stopcock valve, the stopcock actuator comprising aninternal conduit defining a first conduit portion, a second conduitportion, and a third conduit portion of reduced diameter relative to thediameter of the first conduit portion, wherein the stopcock actuator isconfigured to provide a change in a fluid mixture ratio of the firstfluid and at least the second fluid based on a position of the stopcockactuator.
 23. The method as claimed in claim 22, further comprising:providing a flow meter associated with at least one of the fluid lines;and providing a controller adapted to effect a positional change of thestopcock actuator at least in part based on feedback from the flowmeter.
 24. The method as claimed in claim 22, wherein the first fluidline has a first diameter, the at least second fluid line has an atleast second diameter, and wherein the first diameter differs from theat least second diameter.
 25. The method as claimed in claim 22, whereinthe outlet of the pump is configured for connection with a patientinterface device.
 26. The method as claimed in claim 22, furthercomprising: connecting the second end of the first fluid line to thefirst input port of the mixing stopcock valve, and the second end of theat least second fluid line to the at least second input port of themixing stopcock valve; and connecting the outlet port of the mixingstopcock valve to the inlet of the pump.
 27. The method as claimed inclaim 22, further comprising: actuating the stopcock actuator to effecta positional change in a position of the stopcock actuator to provide achange in a fluid mixture ratio of the first fluid and at least thesecond fluid.